Running Sleuth in a process along embedded Neo4j instance will result in blocking.

Describe the bug By default, sleuth will attach to all Executors assuming everything is based on Spring and can be ignored with spring.sleuth.async.ignored-beans. However, for running heavier libraries such as Neo4j this is not enough.

Sample Currently, an call to the embedded neo4j service will block on the following:

"neo4j.BoltWorker-5 [bolt] [/127.0.0.1:54607] @6931" prio=5 tid=0x1c nid=NA waiting for monitor entry
  java.lang.Thread.State: BLOCKED
	 waiting for Test worker@1665 to release lock on <0x598e> (a java.util.concurrent.ConcurrentHashMap)
	  at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:183)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:517)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:533)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:505)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:482)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:475)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1158)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveBean(DefaultListableBeanFactory.java:422)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:352)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:345)
	  at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1126)
	  at org.springframework.cloud.sleuth.internal.LazyBean.get(LazyBean.java:64)
	  at org.springframework.cloud.sleuth.instrument.reactor.ReactorSleuth.lambda$scopePassingSpanOperator$0(ReactorSleuth.java:104)
	  at org.springframework.cloud.sleuth.instrument.reactor.ReactorSleuth$$Lambda$3687/0x0000000801c491a0.apply(Unknown Source:-1)
	  at reactor.core.publisher.FluxLift.subscribeOrReturn(FluxLift.java:50)
	  at reactor.core.publisher.Flux.subscribe(Flux.java:8311)
	  at reactor.core.publisher.Flux.subscribeWith(Flux.java:8494)
	  at org.neo4j.fabric.stream.Rx2SyncStream.<init>(Rx2SyncStream.java:45)
	  at org.neo4j.fabric.bolt.BoltQueryExecutionImpl.<init>(BoltQueryExecutionImpl.java:55)
	  at org.neo4j.fabric.bolt.BoltFabricDatabaseService$BoltTransactionImpl.executeQuery(BoltFabricDatabaseService.java:166)
	  at org.neo4j.bolt.runtime.statemachine.impl.AbstractTransactionStateMachineSPI$AbstractBoltResultHandle.start(AbstractTransactionStateMachineSPI.java:135)
	  at org.neo4j.bolt.runtime.statemachine.impl.TransactionStateMachine$State.startExecution(TransactionStateMachine.java:534)
	  at org.neo4j.bolt.runtime.statemachine.impl.TransactionStateMachine$State$2.run(TransactionStateMachine.java:330)
	  at org.neo4j.bolt.runtime.statemachine.impl.TransactionStateMachine.run(TransactionStateMachine.java:84)
	  at org.neo4j.bolt.runtime.statemachine.impl.TransactionStateMachine.run(TransactionStateMachine.java:77)
	  at org.neo4j.bolt.v4.runtime.InTransactionState.processRunMessage(InTransactionState.java:81)
	  at org.neo4j.bolt.v4.runtime.InTransactionState.processUnsafe(InTransactionState.java:48)
	  at org.neo4j.bolt.v3.runtime.FailSafeBoltStateMachineState.process(FailSafeBoltStateMachineState.java:48)
	  at org.neo4j.bolt.runtime.statemachine.impl.AbstractBoltStateMachine.nextState(AbstractBoltStateMachine.java:143)
	  at org.neo4j.bolt.runtime.statemachine.impl.AbstractBoltStateMachine.process(AbstractBoltStateMachine.java:91)
	  at org.neo4j.bolt.messaging.BoltRequestMessageReader.lambda$doRead$1(BoltRequestMessageReader.java:90)
	  at org.neo4j.bolt.messaging.BoltRequestMessageReader$$Lambda$3064/0x0000000801939af0.perform(Unknown Source:-1)
	  at org.neo4j.bolt.runtime.DefaultBoltConnection.lambda$enqueue$0(DefaultBoltConnection.java:148)
	  at org.neo4j.bolt.runtime.DefaultBoltConnection$$Lambda$3065/0x0000000801939d18.perform(Unknown Source:-1)
	  at org.neo4j.bolt.runtime.DefaultBoltConnection.processNextBatchInternal(DefaultBoltConnection.java:237)
	  at org.neo4j.bolt.runtime.DefaultBoltConnection.processNextBatch(DefaultBoltConnection.java:172)
	  at org.neo4j.bolt.runtime.DefaultBoltConnection.processNextBatch(DefaultBoltConnection.java:162)
	  at org.neo4j.bolt.runtime.scheduling.ExecutorBoltScheduler.executeBatch(ExecutorBoltScheduler.java:246)
	  at org.neo4j.bolt.runtime.scheduling.ExecutorBoltScheduler.lambda$scheduleBatchOrHandleError$3(ExecutorBoltScheduler.java:229)
	  at org.neo4j.bolt.runtime.scheduling.ExecutorBoltScheduler$$Lambda$3068/0x000000080193a3c8.get(Unknown Source:-1)
	  at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1764)
	  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
	  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
	  at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	  at java.lang.Thread.run(Thread.java:832)

[ahassany]

2.2.6.RELEASE and 2.2.7.BUILD-SNAPSHOT

[marcingrzejszczak]

OK! Ping us back once you can reproduce the issue.